Hinduism is the fourth largest religion in the world and is the oldest among major religions. Historians believe that it originated more than 5000 years ago. Hinduism is the first Dharmic religion. It is often referred to as "the religion of India;" about 800 million of the world's billion Hindus live in India, so about 80 percent of Hindus are Indians. According to a recent American survey, Hindus are the best educated and among the richest religious groups in the United States.
Hindus believe in reincarnation and eventual communion with Brahman (God) as well as respect for all life forms. Their holy writings are known as the Vedas. Hindus outline the four goals of various humans (purusharthas) as: dharma (righteousness), artha (material success), kama (love/pleasure), and moksha (release from reincarnation/reunification with Brahman); above all four of these, in certain Hindu schools, is the goal of pure Love of God.
Definition by law
In 1966, the Supreme Court of India defined what Hinduism is for legal purposes:
1. Belief in the authority of the Vedas (an ancient collection of hymns to the gods, written in Sanskrit). The oldest collection of hymns in the Vedas is the Rig Veda, which was written between 1800 and 1300 B.C. The greatest Veda hymn is the “Bhagavat Gita,” a section in the Mahabharata concerning life’s never-ending spiritual journey towards perfection. Bhagavat Geeta is rendered as a dialogue between Shri Krishna (incarnation of Vishnu) and Arjuna (the great archer) in the middle of the battlefield.
2. Spirit of tolerance and willingness to understand and respect an opponent’s view.
3. Belief in world rhythms: long periods of creation, maintenance and dissolution follow each other in endless succession.
4. Belief in reincarnation (rebirth) and preexistence.
5. Belief that there are many ways to salvation.
6. Unlike most other religions, Hinduism is not defined by a specific set of philosophical concepts.
7. Belief in one god. Contrary to popular belief, Hinduism is not a polytheistic religion. The Vedas, the primary Hindu holy scriptures states that there is only one God but can manifest in many forms. This is the reason why there are many deities. A common example used to explain this is that an individual can be called different names depending on the relationship has with another. A man can be a son to his parents, a nephew to his uncle, a father to his son, and a husband to his wife all at the same time. None of these different relationships suggest multiple people but rather different aspects of one person. The same is applied to God in Hinduism, which has no form and is infinite. Hindus may call God, Paratman (Supreme Soul), Brahmana (Eternal Spirit), or Ishvara (Supreme Lord). Deities have various names but represent aspects of God that manifest in the world. For example Agni (fire, Divine spark), Vayu (wind, or breath which could mean life force, Indra (in mythology king of gods but also refers to the senses such as vision, hearing, touch, taste), and Lakshmi (fortune).
8. Secular multiplicity and accommodating flexibility in spiritual practices.
Relations between Hinduism and Christianity have also been shaped by unequal balances of political power and cultural influence. Although communities of Christians have lived in South India since the middle of the 1st millennium, the great expansion of Indian Christianity followed the efforts of missionaries working under the protection of the British colonial government. 
Some state governments such as Gujrat, Madhya Pradesh have passed anti-conversion laws, attempting to prevent Hindus from being forced or coerced into converting to other religions such as Islam and Christianity.
For more on Hinduism, see World History Lecture Three.
In Hinduism, according to one classification, believers are categorized into four distinct categories, acording to their beliefs.
- Advaita Astika: Believer of God & Believer of Scripture
- Advaita Nastika: Believer of God & Non-believer of Scripture
- Dvaita Astika: Non-believer of God & Believer of Scripture
- Dvaita Nastika: Non-believer of God & Non-believer of Scripture
Sati was a practice during the medieval period whereby still-in-love Hindu widows jumped into the funeral pyre for the their husbands(together till death). It was developed in a blatant misinterpretation of their scriptures. In modern times, family members of the husband forced widows to burn to death. Thus this practice was abolished in the 19th century by the efforts of Ram Mohan Roy and Lord William Bentinck.
Hinduism also has a "caste by profession" or varna system. Traditionally Hindu society is divided into four castes:
- Brahmin (the highest caste in Hinduism)
- Kshatriya (the warrior or ruling class)
- Vaishya (merchants)
- Shudra (unskilled laborers and servants)
In ancient times, caste was determined by profession, and could be changed by changing career. As time passed on, both Caste and Profession became defined by birth. 
Shudras were the lowest caste and were denied of many rights in past. Apart from these four main castes, there was a new addition in the modern distortion of the caste system, as the lowest caste and without any rights, called the Dalit (Untouchables). Historically these dalits are the victims of discrimination by higher castes. Even today there are many reports of discrimination against dalits.
- Johnson, W. J. A Dictionary of Hinduism (2009) excerpt and text search
- Knott, Kim. Hinduism: A Very Short Introduction (2000) online edition
- Shattuck, Cybelle. Hinduism (1999) online edition
- Sullivan, Bruce M. Historical Dictionary of Hinduism (1997)
- Werner, Karel. A Popular Dictionary of Hinduism (1997) excerpt and text search
- Zaehner, R. C. Hinduism (1966) online edition
- The largest being Christianity, Islam, Secular/Nonreligious/Agnostic/Atheist, and Hinduism, in that order
- Origin of Hinduism (About.com)
- Census of India, religion data, brief analysis (PDF); "At the national level, of 1028 million population, 828 million (80.5 percent) have returned their religion as Hindus followed by 138 million (13.4 percent) as Muslims and 24 millions (2.3 percent) Christians. 19 million (1.9 percent) persons follow Sikh religion; 8 million (0.8 percent) are Buddhists and 4.2 million (0.4 percent) are Jains as per the 2001 Census. In addition to these, 6.6 million belong to ‘Other Religions and Persuasions’ including tribal religions which are not part of the six main religions stated above. About seven lakh (or 0.7 million) persons have not stated their religion."
- Hanerjee, Neela, Americans Change Faiths at Rising Rate, Report Finds, New York Times, 25th February, 2008.
- Hinduism and Christianity Encyclopædia Britannica.
- India: International Religious Freedom Report 2003 (U.S. Department of State)
- The Caste System
- The caste system BBC
- Dalits face discrimination in southern Tamil Nadu All India Christian Council
- India: ‘Hidden Apartheid’ of Discrimination Against Dalits Human Rights Watch